Conversion of hydrocarbons



Patented-lune 11, 194i? PATENT OFFICE CONVERSION OF HYDRQGABBONS Hans Tropsch, deceased, late of Chicago, 111., by Carl W. von Helmolt, administrator debonls non, Chicago, 11]., asslxnor to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No- Drawing.

Continuation of application Serial" No. 37,342, August 22, 1935.

This application January '24, 1938,8erial No. 186,889

11 Claims. ((1195-52) This application is a continuation of co-pend ing application filed in the name of Hans Tropsch, Serial No. 37,342, filed August 22, 1935.

This invention relates particularly to the conversion of hydrocarbon fractions produced from naturally-occurring petroleums and particularly the distillate portions thereof, though the process may also be. applied to analogous fractions produced in the primary distillation of more or less solid hydrocarbonaceous material such as coals, shales, ligniteaetc. More specifically, the invention is concerned with a process for converting a substantial portion of relatively heavyhydrocarbon fractions into lower boiling fractions suitable for :useas motor fuel in automotive engines, the feature of the-process whichwill be developed in more detail in the following specification being the employment of a particular class of compact materials til for accelerating the catalyticdecomposition re actions, so that more moderate temperatures and pressures may be used than these common to the majority of hon-catalytic cracking processes.

In the? ordinary cracking of hea /y hydrocarbon fluids toproduce economic yields of motor fuel, the conditions of operation in regard to temperature, pressure and time of exposure to cracking conditions are quite severe and. the present day tendency is toward the use oi conditions of inso creasing severity, since this seems to be the only way to meet the demaudfor motor fuel of high antilrnock value. The use of temperatures of the order of 950 to 1109" Ft, with pressures of several hundred pounds per. square inch, requires the use of very special metals adapted to withstand the strain without undue hazards, and it is obvious that the use of these severe conditions is attended with" greatly increased expense in addition to greater danger. 4,0 Catalysts have seemed to ofier the solution to the cracking problem in making possible the use of lower temperatures and pressures to accomplish the results obtainable at considerably higher temperatures and pressures without catalysts, 5 However, in spite of a large amount of experimenting, but few catalysts have been developed which meet the requirements of low cost, resistance to poisoning influences and general ruggedness of structure, in addition to possessing the power to accelerate the cracking reactions in the desireddirections. The better metal catalysts,

such as nickel or cobalt. have a tendency to cause 2 i the splitting of! of undue amounts'of hydrogen and light gases in preference to fostering cracking reactions, and in addition are quickly rendered inert when used with sulfur-containing oils on account of their conversion to sulfides which possess only low catalytic properties.

In one specific embodiment the present inven-' 1 tion comprises the cracking or conversionof hy-' s drocarbon distillates for the production of low boiling motor fuel fractions therefrom in the presence of catalysts, comprising modified feldspars which have been treated for the removal of a substantial portion of their alkali metal 10 and aluminum content and then caused to adsorb minor amounts of promoters from metal salt solutions.

As a result of extended investigations it has been found that catalysts of the character menlid tioned possess unusual value in cracking reactions. To assist in developing the character oi the preferred catalysts, the following brief tie-- scription of the feldspars as a mineral group is given:

The feldspars are ortho silicates of alkaliand/or alkaline earth metals and aluminum, the

alkali and alkaline earth metals being in isomorphous mixtures. The general formula for the feldspar minerals is: (RBI) AlSisOs, in which R represents an alkali metal, usually sodium or potassium, and R represent an alkaline earth metal, usually calcium or barium, since the field spars are quite uniformly characterized by the complete absence of magnesium and iron. R as and R may be considered collectively under the term alkalinous metal. The following table gives the names and formulas of the principal minerals of the feldspar group, these being taken from "A System of Mineralogy by Dana, fith editiompage 314.

Fnziosrsa Group a. .Monoclinic section Orthoclase Q0 Soda-orthoclasee (K,Na)AlSi3Oa Hyalophane (KaBalAlzShQra i b. Triclinic section Microcline; mussel 4s Soda-micr'oclin (K,Na)A1SisOa Anorthoclase (Na,K)AlSiaOa Amientinue series Alb mmseoa so a moses labradorite. DCaAhShOs Anorthite u The general characteristics of the feldspar v minerals are their crystallization in the monoclinic or triclinic systems; theircle'avage in two similar, directions at an angle of about 90; theirhardness, falling between 6 and 6.5;.the1r specific gravity, falling principally between 2.55 and 2.75, .and their colors, being white or pale yellow, red or green.

shadesof According to the concept of the present invention, the naturally-occurring feldspar minerals,

which are abundant and relatively cheap, are altered inboth chemical nd, Physical characteristics by the removal 01' a-considerable proportion of their alkali metal and aluminum components and absorption of minor amounts of metal .salts -from aqueous solutions thereof, this combinationof treating steps yielding catalytic material of markedly e ter potency than the original fields par or the intermediate material after the treat; ment for the removal of the alkali metals and aluminum. The general procedure for eiiecting the treatment oi feldspars accordingto this procfrom Step 1 to remove soluble material, princiess is given below:

, 1'. .The heating in the dry condition of'propor tioned mixtures of feldspar, lime and calcium chloride.

2. The washing of the treated feldspar particles pally sodium and'potassium chlorides, along with part of the calcium chloride used as a reagent.

3, The further treatment of the partially altered feldspar with a mineral acid, followed by washing to remove aluminum, lime and-calcium chloride.

4.. The digestion of the treated feldspar with solutions 01 metal salts, principally those oi aluminum and the heavy metals (those having a specific gravity of over 4) to efi'ect the adsorption of small amounts of metal salts on to the more or less activated residue of the feldspar molecules.

5. The final calcination of the treated material to decompose at least a portion of the adsorbed 1 salts to release acid radicals and remove water and form a certain amount of metal oxides whichapparently act as promoters. l

The following specific example of the preparation of altered feldspar cracking catalyst-is givento illustrate the general method;

= Five hundred parts by weight each of finely ground orthoclase, lime, and calcium chloride were'intimately mixed and heated for about 3 hours at a temperature of 1202 F. (650. C.) The partially fused mix was allowed to cool, pulverized, and washed with about 2 volumes of water. By this washing step, potassium chloride was extracted, this being recoverable on evaporation of the wash water. The washed material was then digested with about 4 volumes era 10 pen-cent hydrochloric acid, after which the remaining insoluble material was washed with water first by decantation and later by filtering until substantially no chlorides were present in the wash water. The treatedfeldspar particles were thenadded to an aqueous solution consisting of 33.3 weight oihydrated aluminum'sulfate in about 3,000 parts by weight of water, and the V suspensionwasthendigestedattheboilingpoint of the solution, using a reflux condenser tor: a

period of about 18 hours. The particles were again washed by decantation and later by filtering until the wash water contained no sulfates. By this final treating step asmall amount of aluminum salt apparently probill]! in Ofa partially hydrolysed sulfate partsby which was then 7 the treated feldspar for some time at atemperature of about 1000 F. I

Following the above general procedure, it is possible to prepare a co derable number of alternative catalysts in w ch salts of other metals than aluminum, for example, iron, nickel, cobalt,

chromium, molybdenum, tungsten, zinc, cadmium, copper etc., have been adsorbed on the preliminarily treated feldspars. Such modified Ieldspars an exhibit a considerably improved catalytic eiiectiveness when compared with the decomposed to oxide by original feldspar mineral, but theeflfect oi the flnal treatment by different metal salts upon the catalytic properties of various dealkalized feldspars varies considerably, and it is not to be inferred that the different alternative catalysts which may be produced by the general procedure outlined-are in any sense equivalents among themselves in any one-cracking reaction or'in difi'erent cracking reactions. Thus the catalysts may vary from being specific for breaking the to carbon or carbon-to-carbon bond or cracking hydrogen.

It is comprised within the scope of the invention to treat any representative of the feldspar group of minerals first for the removal of a portion or substantially all of the alkali metal content, second for the removal of a portion or substantially all of thealuminum content, and then with difierent metal salts either single or in combination to further enhance their catalytic properties. Practically any soluble salt may be emthe removed alkali metals. Analyses of the feldsparsafter treatment with metal salt solutions indicate that there is no stoichiometric relationship between the amount of alkali metals removed and the amount of metal salts adsorbed, that the metal salts are held by adsorptive and not by the usual volume forces and that their oxides produced by calcination act as catalyst promoters. The phenomenon of promoter catalysis is none too well understood at the present time :nd the present instance is merely cited as one manifestation of the general law.

By the use of catalysts of the present character, itis possible to efiect cracking or hydrocarbon distillates which are more or less readily vaporizable at temperatures and pressures considerably lowerfthan those necessary for produdng motor fuel fractions of a required antiknock value with-, 00

out. the use of catalysts. As stated prevmusly,

the common range of cracking temperatures chosen to produce premium motor fuel Iractions from heavy petroleum distillates variu from about 950.to l F. and the pressure employed under these conditions varies from about' 100 to 500 polmds per square inch. when the present type of catalysts are employed, it is seldom necessary to use temperatures over 950 E; e. g., a range of 850 to- 950 F. is satisfactory; and further, it is only necessary to employ atmospheric or very slightly super-atmospheric pressures. The increased rate of cracking makes possible the use of the same throughput of oil for .an apparatus of a given volumetriccapacity was possible is at high super-atmospheric pressure, and. 'secondly, permits the use of much thinner tubes and reaction chambers, with considerably reduced costs. v

The preferred method of operation when usi g catalysts of the present character is to heat and vaporize the oil to be cracked during passage through a tubular heating element wherein the temperature is raised to the best point for contact with the catalyst and then pass the vapors downwardly through a bed of granular catalyst particles contained in a vertical cylindrical treating chamber to effect the cracking reactions.'

The size of the particles which are most economically employed will vary somewhat but is usually comprised within the range of! to .20 mesh; After the cracked materials leave the catalyst chamber, they are subjected to fractionation to separate fixed gases, range distillates, fractions suitable for recycling, and materials which are generally unsuitable for further cracking. It is generally preferable to operate the cracking process when using the present type of catalyst in such a way that there is a limited conversion per pass and if desired the recycle fractionsmay be subjected to further catalytic decomposition in contact with different catalysts and at different temperatures, or under conditions better suited-for their conversion.

The following example is given to show the general character of the results obtainable by the use of catalysts class covered by the present invention. The data given are typical but are not introduced for the the invention, since other examples of a generally similar character are available.

An orthoclase feldspar was treated for the removal of alkali metals and aluminum and later I subjected to treatment with aluminum sulfate solution to permit theabsorption of aluminum sulfate as described in a preceding paragraph.

The following data are introduced to indicate in a general way the effect of the treatment on 5 the chemical compositionof the original feldspar.-

. aluminum followed by the treatment withalu minum sulfate solution'and the final calcining, leaving out the water content" in all instances V 1 2 3 i Constituent 0 Re laced rtho- Treated clase g a g orthoclue 64.8 12.0 59.1 18.2 27.4 7.2 17.0 0.0 1.9 Undetermin 0.0 0.0 1.8

Analyses of gases evolved during the calcining step showed oxides of sulfur, indicating that the originally adsorbed aluminum sulfate had de-' 0 composed to aluminum oxide.

Using the above prepared catalyst in a fineness of 6 to 10 mesh in a vertical cylindrical catalyst chamber the vapors of a Mid-Continent-gas oil were passed downwardly therethrough at a tem- 75 perature of 932 F. and a slight superannospheric gasoline boiling falling within-the general purpose of correspondingly limiting the scope of pressure to'ensureproper flow through the reactor and succeeding fractionating equipment. The rate of feed of the gas oil was regulated so that the initial conversion per pass was 'of the order I of 25 per cent, based on 400 F. end-point gasoline production. The recyclestock falling within the same proximate range as the original gas oil was I separately recracked in contact with the same type of catalyst at the same temperature but at a somewhat reduced feed rate, the products from the cracking zone operating upon the recycle stock being introduced into a common fractionator with the products from the primary cracking operation. I The following table shows the principal significant. data obtained as the result of an extended period of operation:

' Cascxmo Rrsun'rs Per cent 400 Rand-point gasoline 52 Per cent Diesel fuel 20 Per cent residuum 20 Gas loss 8 Pnorna'rms or Gssounn as Gravity A. P.,I 56 Initial boiling point; F 100' over at "F 275 End boiling point F .399 Octane number 82 m The practical value of the present invention can be readfly seen from a consideration of the a above figures, since it is fairly well known that gasoline having an anti-knock rating corresponding to over 80 octane number is not producible in the yield indicated under non-catalytic cracking conditions and particularly at low pressure. The gasoline produced as a result of the above run was readily stabilized by the addition of small amounts of commercial inhibitors which preserved its olefinic content from deterioration over a sufficient time to permit its storage under average refinery conditions.

The foregoing specifications and single exam-- ple are sumcient to disclose the character of the 45 present invention and its practical value though neither section is intended to be unduly limiting 'upon its proper scope.

- ature with a modified feldspar produced by removing from feldspar at least apart of its alkalinous base and aluminum content, adsorbing on the residual portion of the feldspar, fromaqueous solution, a salt of a metal whose oxide iscatalytic and then calcining to convert said salt to the cati alytic metal oxide supportedon the residual portion of the feldspar.

2. A hydrocarbon oil conversion process which my comprisescontacting the oil at cracking temperature with a modified feldspar produced by removing from feldspar at least a part ofits alkalinous base and aluminum content, treating the residual portion of the feldspar with an aqueous aluminum salt solution to adsorb aluminum saltthereon and then calcining to convert the adsorbed salt to aluminum oxide supported on the residual portion of the feldspar.

3.- A hydrocarbon il conversion process which w comprises subjecting the oil to cracking conditions in the presence of a catalyticmetal oxide supportedon a feldspar whose alkalinous base and aluminum content has been removed at least in part. am

4.,A hydrocarbon oil conversion process which comprises subjecting the oil to cracking condiai'eldspar whose alkalinous base and aluminum content has been removed at least in part,

6. A hydrocarbon oil conversion process-which comprises subjecting the oil to cracking condi-. tions inthe presence of nickel oxide supported on a feldspar-whose alkalinous base and alumi- 7 mm content has been removed at least in part.

7. A process for producing gasoline from hydrocarbon oils heavier than gasoline which comprises subjecting the heavier oil to cracking 'conditions in the presenceot a modified feldspar Produced by removing from feldspar at least a part of its alkalinous base and aluminum content. treating the residual portion of the i'eldspar with an aqueous aluminum sulfate solution to adsorb aluminum sulfate thereon and then calcining to convert the adsorbed sulfate to aluminum oxide supported on tion of the feldspar. j 8. The processes defined in claim I further characterized in that said metal is iron,

9.,The process as defined in claimi further characterized in that said metal is nickel.

10. Aprocess for the conversion 01 hydrocarbon distillates to'produce lower boiling hydrocarbons therefrom suitable for use as motor fuels; which comprises subjecting the vapors of said the residual por aaoaaso hydrocarbon distlllates at a conversion temperature of the order of 850-1000 I". and at substantially atmospheric pressure to contact with granular catalytic materials produced by heating feldspar-s with calcium oxide and calcium chloride mixtures followed by washing tor the partial removal of alkalinous bases and aluminum, subjecting said treated ieldspars to further treatment with solutions of metal salts to permit ad-' sorption oi said salts, and further drying and calcining said treated feldspars to volatilize a sub- -stantlal portion of the acid radicalspt said salts and leave residual catalysts. I g

11. 'A process for the conversion of hydrocarbon distillates to produce lower boiling hydrocompounds which function as carbons therefrom suitable for use as motor fuels}.

which comprises subjecting the vapors of said hydrocarbon distillatesat a conversion temperature oi! the order oi,850-1000 F; and'at substantially atmospheric pressure to contact with granular catalytic materials produced by heat ing teldspars with'calcium oxide and calcium chloride mixtures followed by washing for the partial removal of alkalinous bases and alumiiii num, subjecting said treated ifeldspars to treatment with solutions or heavy metal salts to perinit'adsorption of said salts. and further drying and calcining said treated ieldsparsto volatilize a substantial portion of the said acid radicals 01' said salts, and leave residual compounds which functionas catalysts.

CARL w; vim moron; Administrator de Bonis Non With .Will Annezed of the Estate of Hams Tropsch; Deceased. 

